Psoriatic arthritis (PsA) is a type of inflammatory arthritis that is unique in that it can affect both the joints and the skin.
Inflamed joints in arthritis can be swollen and painful while patches of inflamed skin called psoriasis can be itchy and scaly.
Psoriatic Arthritis can also affect other parts of the body including tendons in the feet, knee, hips, or ribs.
Psoriatic Arthritis belongs to a family of diseases called the seronegative spondyloarthropathies. Other members of this family include ankylosing spondylitis, reactive arthritis and enteropathic arthritis.
Psoriatic Arthritis is an autoimmune disease, meaning that it occurs when the body’s immune system attacks its own healthy cells and tissues. The reason why it does this is not well understood. When the body’s immune system is “activated” in this way, it can make a person feel very tired, similar to when they have the flu.
Who Gets Psoriatic Arthritis
About 1 in every 3 people who get psoriasis will eventually develop psoriatic arthritis.
Psoriatic Arthritis tends to run in families, which means that genetics likely is a big factor in terms of who gets Psoriatic Arthritis. If a person has family members who have Psoriatic Arthritis, they have a higher risk of getting it themselves.
People who get Psoriatic Arthritis usually start experiencing symptoms between 30 to 50 years of age.
Understanding Psoriatic Arthritis
Psoriatic Arthritis is a type of arthritis that can create symptoms in the joints and skin. It usually affects people with a skin disease called psoriasis.
Psoriatic Arthritis can be a tricky form of arthritis because it can appear very different between patients.
Like other types of inflammatory arthritis, the main target of the immune system attack in Psoriatic Arthritis is the joints.
Joint and Tendon Inflammation
Psoriatic Arthritis can cause various degrees of discomfort and problems with joint mobility. In most cases, only a few joints are affected at first. Over time, more joints can become affected.
Symptoms of joint pain and stiffness are usually worse in the morning or after periods of inactivity (such as sitting for a long time). In cases where Psoriatic Arthritis is not too severe, these symptoms usually get better after certain exercises and activities.
In advanced stages of Psoriatic Arthritis, the disease can also affect other parts of the body such as the tendons at the backs of the heels (achilles tendon), under the bottoms of the feet, around the knee, on the outside of the hips, or those between the ribs can become inflamed.
Psoriatic arthritis can affect the joints in different ways. There are five basic patterns:
- The most common pattern is for a few joints to be affected. In other words, Psoriatic Arthritis “picks on” a few different joints, like the knee, a wrist, or a finger.
- Sometimes many joints are affected. This type of Psoriatic Arthritis can look a lot like rheumatoid arthritis.
- Joints at the ends of the fingers or toes may be involved. Psoriatic Arthritis can cause fingers and toes to swell up like sausages, a condition called dactylitis.
- Joints in the spine are sometimes – but not often – involved. This usually happens later in the course of the disease. It is less common for the joints in the back to be involved from the start of Psoriatic Arthritis but it can occur.
- The least common type of Psoriatic Arthritis is a very destructive form of the disease. It is called arthritis mutilans. This type of Psoriatic Arthritis can be especially painful.
Fatigue is a common symptom of Psoriatic Arthritis because the body’s immune system is activated (turned on) similar to when it is fighting the cold or a flu.
Skin Symptoms (Psoriasis)
In Psoriatic Arthritis, the immune system’s attack on the skin can cause it to become inflamed and appear red. In some cases, these areas may covered by a silvery-white scale called plaque.
In most people with Psoriatic Arthritis, the psoriasis is relatively mild and is usually experienced long before any arthritis symptoms. Many never realized that that they had this condition before their doctor suspected they might have Psoriatic Arthritis. Psoriasis can also sometimes hide in places like the scalp. It’s also possible for patients to have arthritis symptoms long before any psoriasis symptoms.
Pitting of Fingernails and Toenails
Psoriasis can affect the fingernails and/or toenails. When this happens, the nails can be pitted. In some cases, the nails can lift off the nail bed.
Eye Inflammation (Iritis)
Rarely, inflammation can also affect the eye with a condition called iritis.
Psoriatic arthritis is best diagnosed by a rheumatologist, a type of doctor that specializes in arthritis and autoimmune disease.
To diagnose Psoriatic Arthritis, a doctor will take a careful and complete history and perform a thorough physical examination.
Among many other considerations, doctors will look for specific things that are signs of Psoriatic Arthritis such as dactylitis (swollen fingers and toes that can look like “sausage fingers”), psoriasis, and painful and swollen joints.
Blood tests and x-rays will likely be ordered to confirm the diagnosis.
Common Tests to Diagnose Psoriatic Arthritis
Looking for inflammation: Psoriatic Arthritis is an inflammatory arthritis so these tests are expected to have abnormal results. However, it’s possible for a person with Psoriatic Arthritis to have normal blood test results.
Common tests for inflammation include the Complete Blood Count (CBC), Erythrocyte Sedimentation Rate (ESR), and the C-Reactive Protein (CRP) test.
X-rays looking for signs of Psoriatic Arthritis and for joint damage: X-rays can sometimes be helpful in diagnosing Psoriatic Arthritis because the disease can cause some specific changes not found in other types of arthritis. Most of these changes are only seen in later stages of Psoriatic Arthritis.
Scans can also help physicians assess any possible damage to the joints caused by the disease.
Psoriatic arthritis occurs when the body’s immune system begins to attack its own joints as well as the skin. The reason for this is not well understood.
It is thought that genetics plays a role in who gets Psoriatic Arthritis because the disease tends to run in families. People who have family members affected by Psoriatic Arthritis have a higher chance of having Psoriatic Arthritis themselves. Sometimes, a whole family can be affected by the disease.
Psoriatic Arthritis must be treated early and aggressively to avoid permanent damage to the joints and tendons, and reduce the risk of long-term inflammation in the body such as heart attack or stroke.
People with Psoriatic Arthritis can lead active and productive lives with the right kinds of treatment.
Skin Care for Psoriasis
Skin care is often an important part of a Psoriatic Arthritis patient’s treatment plan. If psoriasis is severe, it can be helpful to consult a dermatologist.
Psoriasis can be improved with certain creams and lotions. Topical therapy (treatments applied directly to the skin) is often used together with other medications that control the joint inflammation seen in Psoriatic Arthritis.
Many people with psoriasis benefit from moderate exposure to sunlight. It’s important to avoid over-exposure, which can cause skin damage, and take steps to avoid sunburn.
Some of the medications used to treat the arthritis side of Psoriatic Arthritis are also helpful for psoriasis including corticosteroids (prednisone), some Disease Modifying Anti-Rheumatic Drugs, and some Biologics.
Non-Steroidal Anti-Inflammatory Drugs
Non-Steroidal Anti-Inflammatory Drugs are medications that reduce the inflammation of joints caused by Psoriatic Arthritis. They also help to reduce symptoms such as pain. There are about 20 different anti-inflammatory medications available, so if one doesn’t work for someone, their doctor can recommend another one to try.
Medications like prednisone can help control inflammation in some people. It can also help control symptoms of pain and stiffness. It is usually used in high doses for short periods of time. When used for long periods of time, prednisone can have side effects.
Some people with Psoriatic Arthritis also benefit from cortisone injections directly into affected joints.
People with Psoriatic Arthritis should to discuss the risks and benefits of using corticosteroids with their rheumatologist.
Analgesic Medications for Pain
Analgesic medications only control pain. They do nothing to control the disease or to prevent further joint damage. Analgesics can range from simple things like Acetaminophen or Paracetamol to more potent narcotics like morphine.
Disease Modifying Anti-Rheumatic Drugs (DMARDs)
Disease Modifying Anti-Rheumatic Drugs were initially used to treat rheumatoid arthritis, and they are also effective in treating people with psoriatic arthritis.
Methotrexate is the most commonly used medication to treat Psoriatic Arthritis. Methotrexate offers “two for one” treatment because it is effective at treating both the arthritis and psoriasis symptoms of Psoriatic Arthritis.
Other types of Disease Modifying Anti-Rheumatic Drugs work well for treating the arthritis, but are not as helpful for the skin. Other Disease Modifying Anti-Rheumatic Drugs that are commonly used include: Sulfasalazine, Leflunomide (Arava), Hydroxychloroquine (Plaquenil), and Gold (myochrisine). Another other options that can also be beneficial is Otezla (Apremilast).
Advanced Therapeutics - Biologics and Small Molecules
Patients with Psoriatic Arthritis whose joint pain and stiffness aren’t adequately controlled by anti-inflammatory medications and Disease Modifying Anti-Rheumatic Drugs can be treated by a class of medications called advanced therapeutics. Advanced therapeutics consist of biologic medications and small molecules. These medications are extremely effective and can make a big difference for people with the disease. They can help improve the symptoms of both arthritis and psoriasis associated with Psoriatic Arthritis.
A type of biologic called anti-Tumor Necrosis Factor biologics was first introduced in 1998. These work very well for many people with Psoriatic Arthritis. Today, a number of anti-TNF biologics are available including Humira (adalimumab), Cimzia (certolizumab) Remicade/Inflectra/Remsima (infliximab), Simponi (golimumab), and Enbrel/Brenzys/Erelzi (etanercept).
Other biologics target a signalling protein called IL-17 which is involved in the inflammatory response. They can work well for psoriasis and Psoriatic Arthritis. These medications include Cosentyx (secukinumab) or Taltz. (ixekizumab)
Other biologics target signalling proteins called IL-12 and IL-23 whic are also involved in the inflammatory response. These biologics tend to work better for psoriasis than they do for arthritis. These medications include Stelara (ustekinumab).
Another class of advanced therapeutics called small molecules which block other parts of the immune system can be very effective treatments. Examples of small molecules used to treat Psoriatic Arthritis include Xeljanz (tofacitinib).
With many advanced therapeutics to choose from, if one doesn’t work for someone, their rheumatologist may suggest another.